Fuel injection system for internal combustion engines



B. WALKER April 6, 1937.

FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed Aug. 20, 1930 2 Sheets-Sheet 3: WALKER April 6,' 1937.

FUEL INJECTION SYSTE FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed Aug. 20, 1930 INVENTOR.

Patented Apr. 6, I937 FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES Brooks Walker, Piedmont, Calif.

Application August 20,

8 Claims.

This invention relates in general to explosive engines of that class in which the fluid which forms the basis of thevexplosive mixture is admitted to the explosion chamber of the engine in proper quantities for each successive charge, and more especially to the means for controlling and regulating an electromagnetic fuel metering valve with the ultimate object of regulating the-speed and power of the engine over a relam tively wide range 'of speed and torque variations.

The object of the invention is to improve such meansin a way that correct metering will be accomplished, particularly at full torque throughout a wide range of speed variations. A further object of the invention'is to' prevent the possibility of the engine being flooded with an excess amount of fuel-at low speeds or when the engine is stopped. Another object is to prothroughout a wide range of speed variations, and

also obtain a wide range of injection duration to affect throttling without the necessity of breaking a large quantity of current at the contacts. The structures now known in this art require a variation in the quantity of current that must be broken at the contact when the throttle is changed, this'is due to the higher value to which the current builds before breaking, this'variation in the magnitude of the current to be broken imposes an unduly heavy load on the contacts at the higher values. The operation L of these electro-magnetically actuated metering valves depends on the very accurate controlof the duration oi. current ,ilow on the individual impulses which energize the valves. trol is determined by .the condition in which the contact surfaces can 'be maintained and the degree to which arcing at, the contacts can be open during any time in which an arc exists. From this consideration it isiapparent that the system which requires the breaking of the least current at the contacts will be the most durable and satisfactory operating system in actual practice, all other things being equal.

A further object of this invention is to provide a system for operating an electro-magnetically 55' actuated metering valve wherein a decided This coneliminated since in practice the valve is held.

1930, Serial No. 476,625

economy of operating current is effected as compared to the systems previously used in this art. This is accomplished by supplying the minimum current input ;to the electro-magnet per energizing impulse regardless of throttle position or frequency of operation- A satisfactory throttle is effected by controlling the decline of flux in the magnetic structure to control the time during which the-valve is held open after the energizing current is discontinued. This is accomplished in my structureby providing a switch mechanism driven by the engine which closes a circuit with the electro-magnet and the source of current supply for a substantially constant period of time throughout a relatively wide range of engine speed, and subsequently connects a variable resistance across the electro-magnetic winding to control the rate of 'decline'of the flux in the magnetic structure. .This control is attained without the addition of anymore supply current than is necessary to just lift the valve. A control of this type is possible because of the difference in the values of the current necessary to lift the valve against the unbalanced fluid pressure prevalent in magnetic valve structuresand against a relatively large air gap, and the current 'values necessary to hold the valve lifted in a balanced fluid condition and with a very muchreduced air gap. In practice a valve was found to lift on 1.5 volts steadily applied and to drop at .2 volts steadily applied. From these figures and from an'engine actually operating on this system it was found that a wide range of control was available for throttling. A means for controlling the decline of magnetic flux has been shown wherein a rectifler was placed in series with a variable resistance across the valve winding in the copending application Serial No. 458,739, flled May 31, 1930,

now Patent No. 1,892,917,, granted January 3, 1933, entitled Magnetic valve" by Brooks Walker-and Harry E. Kennedy, of which I am a co-inventor. This application discloses means for controlling thedecline of flux in a single valve to vary one valve relative to another for equalization in a multi-cylinder engine and shows no way in which a single throttle means could be applied to a multi -cylinder engine.

' A further object of this invention'is to provide an electrical control circuit'inhcrently capable of vmaintaining-the timing of the start of injectlonrelative to the crankshaft a constant at any given engine speed throughout a wide range of throttle changes, this is eifected by leaving the lifting current unchanged and controlling the rate of decline and hence the point of cut-off of injection. This characteristic of unchanged timing of the start of injection during throttle changes at a given engine speed is desirable for economic engine operation and is accomplished by this invention inherently and without the mechanical connections employed in the copending application Serial No. 375,153,

filed July 1, 1929, for Fuel metering or inject-- l0 ing and controlling system for internal combuse tion engines, "by Brooks -Walker and Harry E. Kennedy, of which I am a co-inventor.

I will describe the nature of my invention more explicitly with reference to the convenient and practical embodiments thereof, which I have shown in the accompanying drawings in which:

Fig. 1 is a diagrammatic view of a mechanism embodying the invention.

I Fig. 2 is a view of the contactingmechanism used, illustrated in Fig. l, but shown in different position.

Fig. 3 is a side elevation, partly insection, of an alternative construction embodying the invention.

Fig. 4. is an end view, partly in section, of Fig.

3, through section 6-D.

Fig. 5 is a diagrammatic view of the circuit which may be used in connection with Figs. 3 and 4.

responding parts in the several views and the accompanying drawings.

Referring to the accompanying drawings, and particularly .to Fig. 1, my apparatus includes the electromagnetic fuel valve H, such as described in my co-pending application Serial No. 458,739,-

filed May 31, 1930, or any other well known type.

A fuel inlet pipe 2, delivers fuel from any suitable source of pressure. A section of the engine cylinder is indicated at '3.

A source of electromotive force is, in this case, indicated as the battery 5, though it is to be understood that any source of substantially constant-el'ectromotive force such as a constant voltage generator, will also be satisfactory. The

battery is connected through the variable resistance 4, to screw 1, having a contacting point 7a; This forms a part of the double contacting switch mechanism actuated by the engine ratchet shaft Hi, which may preferably be automatically advanced by a speed sensitive means as the speed of the engine is increased in a manner not here illustrated, but common to' this type of contactor.

The rotation of the ratchet shaft I0, pulls the trigger l I, against the action of the spring l2, to a point where it is forced out of engagement with the ratchet of i0; and is returned against the stop l3, by the spring l2. During this return the point Ha, of the trigger intercepts the point of the hammer l4, and causes it to swing over against the double contacting spring elements 8 and 9, as best illustrated in Fig. 1 The'spring element 9, is connected with the electromagnetic valve bythe wire l5, through the distributor [6,

Y which will preferably be driven froman extension I of the shaft III, in actual practice, and will alternately communicate with different valves.

,The circuit is completed through an electromag netic valve I, to ground as at IT, which forms the return path to the grou ded end 6, of the current source 5. The sprin contactelement 8, is'connected through a variable resistance 20, to groundas' at 3|.

This contactor operates as follows in connec- Similar numerals of reference refer to cortion with the valves: when the contact point 9c,

is in contact with point la, the battery will be connected through the valve to ground, which will cause the valve to lift. The construction of this switch mechanism is such as to form a contact for a fixed period of time, throughout a wide range of engine speed, due to the substantially constant time that the trigger it requires to return to the stop l3 regardless of the speed of rotation of cam l3. the hammer I4 causes the hammer to swing at a given period against the contact spring 8, cansing a constant time contact between the contacts la and 9a while contacts at the end of springs 8 and 9 areseparated. The voltage impressed on the valve is adjusted to the minimum that will cause it to lift through the operation of the contactor, and the variable resistance 4. As the hammer M swings back against its stop it, the contact between To and 9a is broken, as illustrated in Fig. 2, buta new contact is made between the ends of the springs 9 and 3, whicnplaces the variable resistance 28, across the valve coil. This has been found to maintain the valve open for varying periods of time, depending upon the resistance of this circuit, as it controls the rate of decline of flux in the electromagnetic valve, and consequently the lower the resistance 23, the longer will be the duration of the valve opening, and therefore the greater the amount of fuel injected' in the engine cylinder per cycle. A condenser 22, may be placed across the points 9a and To, to decrease sparking.

From the foregoing it is obvious that this structure provides a means whereby the minimum of current is broken at the contact points la and 9a, and that this current remains fixed throughout a wide range of speed and throttlevariations.

In Figs. 3 and i, I have shown an alternative type of contactor. driven by engine means through the gears 3t,'which drive the hollow shaft 3!. 0n the extension of a collar 33, which is rigidly attached to the'hollow shaft 31, the governor weight 32,'is pivotally mounted by means of the pins", 36. The central plane of this governor ,weight 32, lies on an angle with respect to the axial plane of the shaft 3L. This weight is-op- 'eratively associated with a movable collar 35, by means of the ball extension 36. This collar 35, is slidably mounted on the exterior of the shaft 3i, and is yielda'bly urged against the fixed collar 33, by the spring 37, acting against a flange on the opposite end of the shaft 3!. The collar 35, is provided with a pin 38, rigidly attached thereto and passing through the slot 39, in the extension of the collar 35. and through a similar slot in the hollow shaft 3I is rigidly attached to the interior shaft 40, which is slidably' mounted within the hollow shaft'3l,

and through the supporting bearing 4|. At the outer end of the shaft 40, is rigidly attached an insulating coupling 42, forming a driving connection with the cam shaft 43, of the contact device.

This shaft 43, passes through a supporting bear- .ing 44, and is provided with an actuating cam 45, which periodically actuates the contact arm 50. The shaft 43, is further provided w th a slot 43b, through which a pin 46 passes. his pin shaft 43a, so that a lengthwise movement of the shaft 43, will not cause a. similar movement of the shaft 43a. However, both shafts will be kept in a driving relation to each other. Shaft 43a, is provided with distributor actuating cams 46a, 46b, 45c, and 46d, which in turn, actuate The action of the'trigger H on The pin 38, in turn,-

46, is rigidly attached to the.distributor cam thedistributing contact arms "a, 112,410, and Md. The outer end of the shaft 43a, is 'provided with a collector ring 43c, on which a brush 5!. bears. r

In Fig. 4, it will be noticed that the distributing arms and contacting arms are connected to binding posts shown directly above them.

The 0 ration of this contactor is best described in connection with the circuit diagram shown in Fig. 5, in which the source of electro-' motive force Ell, has one end grounded at El, and the other end connected to the contact point 62, by means of a variable resistance 63, and the wire 64. The contact arm 50, periodically makes contact with thepoint 52, for an angle of shaft rotation, determined by the width of the depression 45a, in the cam 45, at the point where a metallicrider-of the timer arm 50, rides, This binding post of this contacting arm 50,, isconnected by means of the common lead 55, to the binding posts ofthe distributor arms 41a, 41b, 41c, and 41d, respectively; These distributor arms make contact withthe valve contact points 66a, 66b, 86c, and 6611, in correct sequence for the proper operation of the valves with respect to the'engine. As the valves have been opened by the passage of current through this circuit, the

cam 45' operates the contact arm 50, to break contact with the point 62, but simultaneously makes contact. through its metallic rider, 5011,,

has one end grounded. The cam 45, and the cams 46a, 46b, 46c, and 46d, are so arranged that while this contact ismade between the arm 50, and the cam 45, one of the valves will still be connected through their respective contacts. A variable resistance 10, is provided, which determines the rate of decline of magnetic fiux in the electromagnetic structure, and thereby provides varying durationsof continued opening after, the contact with the point 62,- has been broken, and since this decline is relatively independent of the speed of rotation (since the valve is assumed to close in all cases before the distributor disconnects that particular valve from the circuit) it willbe seen that a substantially'constant quantity throttle controlmeans. I havefurther provided the minimum load on the contacts relative to the magnitude of the current to be broken by the contacts. I have provided a system well adapted to the current requirements of a circuit supplying 5 the energy to operate fuel metering valve as applied to an engine! a Whilethese figures and illustrations ,of the invention have been applied to a four cylinder motor, it is obvious that the various changes maybe made as to the number of cylinders, and the arrangement, contour, and structure of the various parts within the scope of this invention.

Having thus described my invention, what I claim and desire -to secure by Letters Patent is: 15

' '1. The combination of a reciprocable device, an electromagnet including a coil which operates said device, a circuit including said coil which moves said device in one direction, means which moves said device in the other direction, a second circuitwith a variable resistance including said coil for controlling the rate of decline of flux in the electromagnet, and switch means which peri-' odicallybreaks the first circuit and makes the second circuit.

2. The combination of a reciprocable device, an electromagnet including a coil which operates said device, a circuit including said coil which moves said device in one direction, means which moves said device in the other direction, a second circuit with a variable resistance including said coil for controlling the rate of decline of flux in the electromagnet, and switch means which periodically breaks the,first circuit and makes the 35 second circuit, said first circuit being 'formed for a substantially constant time over a wide range of frequency of formation.

3. The combination of a reciprocable device, an electromagnet including a coil which operates 'said device, a circuit including said coil which of fuel will be delivered to the cylinder per cycle at full throttle setting, over a wide range oi! speed variations- In order that the duration of the contact with the point 62, shall be a substantlally constant time period through the operatedge (1, is so cut as to provide ,an advance in the time of closing of the contact 62, as the engine speed increases. This is of such an angle as to prdvide the best'operating conditions for the motor. i From the'foregoing it is apparent that I have provided a circuit inherently capable of maintaining the timing of the start of injection constant at a given engine speed for throttle changes which vary the duration of injection by varying the point of cut-0E. This is accomplished without auxiliary mechanical connections to the moves said device in one direction, means which moves said device in the other direction, a sec--. ondcircuit with a variable resistance including said coil for controlling the rate of decline of flux 45 in the electromagnet, and switch means which periodically makes the second circuit before it breaks the first circuit- 1 4. The combination of a reciprocable device, an electromagnet including a coil which operates 5 said device, a circuit including said coil which moves said device in one direction, means which movessaid device in the'other direction, a second circuit with a variable resistance including said Y coil for controlling the rate of decline of flux in the electromagnet, and switch-means which periodically breaks the first circuit and makes the sistance, and the other circuit of said switch as- 7 sociated with saidsource of.electromotive force and both said circuits associated with said electromagnet, saiddistributor being driven at variable speeds, said automatic switch firstforming a circuit with said electromagnetjfand said source of 75 electromotive force for a substantially constant time period throughout a wide range of distributor driving speeds, said automatic switch forming a second circuit with said electromagnet and said variable resistance for a decreasing arc of contact duration as the distributor speed in-.

creases and vice versa, said distributor connecting said second circuit before breaking said first circuit.

6. In combination, .arotary power driven distributor, associated with an automatic two circuit switch, an electromagnet, a source of electromotive force, a variable resistance, both circuits of said switch electrically associated with said electromagnet, the first of said circuits forming a closed circuit with said resistance and said electromagnet, and the second circuit connecting said electromagnet with said source of electromotive force, said second circuit being formed for an increasing arc of duration with an increase of distributor" speed of rotation andsaid first circuit being formed for a decreasing arc of duration with an increase of distributor speed.- of rotation and vice versa, said first circuit being formed before said second circuit is broken.

7. In combination, a rotary power driven distributon associated with an automatic double switch, an electromagnet, a source of electromotive force, a. variable resistance, both portions of said double switch electrically associated with said electromagnet, said double switch capable of torming two different circuits with said electrotributor, associated with an automatic double switch, several electromagnets, a source of electromotive force, a variable resistance, both portions of said double switch electrically associated with one of said electromagnets, said double switch capable of forming two different circuits with one of said electromagnets, the first of said circuits being formedwith said source of electromotive force for an increasing arc of duration with an increase of distributor speed of rotation and the second circuit being formed with said resistance for a decreasing arc of duration with an increase of distributor speed of rotation and vice versa, the second said circuit being formed before said first circuit is broken, said distributor connecting, said switch to one of said electromagnets for the formation of both said circuits then connecting said switch to another of said eiectromagnets for connections with said same circuits. I

BROOKS WALKER.

Patent; No. 2,075,877 Granted April 6, 1937 BROOKS WALKER The above entitled patent was extended J uly 24, 1951, under the provisions of the act; of June 30, 1950, for 6 years and 214 days from the expiration of the original term thereof.

Commissioner of Patents. 

